Apparatus for filtering materials



-March 2, 1954 R. P. DUNMIRE 2,670,849

APPARATUS FOR FILTERING MATERIALS March 2, 1954 APPARATUS FOR F ILTERING MATERIALS Filed May 1, 1952 s sheets-sheet 2 l INVENTOR. RUSSELLR DUNMIRE.

BY 0cm R. P. DUNMIRE 2,670,849

March 2, 1954 R. P. DUNMIRE APPARATUS FOR F ILTERING MATERIALS Fild May 1k, 1952 3 Sheets-Sheet 3 Patented Mar. 2, 1954 UNITED STAT-ES FATENT 2,570,849 .AerAnArUs non 'FILTEafINe vMsaltarers Russell 1P.- Donmiro, Deense Qhlo Application May 1,1952, serrano. 285,429

(CL @Mir-45e) i Claims, l l"liis#invention relates to a .ltering .apparatus wherein :the material zto `be ltered is `supplied under pressure .to the .outer surface of a hollow porous filtering wall, the porous ltering Wall being Arotated vto zestablish outwardly thereof a centritugal force which utilized to insure` elliE cient .gltration .or separation .of 4a fluid ,content of .the :supplied material Vfrom solids, `particles and :.suspensoids -.therein. Accordingly, vthe rape parati-1s advantageously Ladapted to filter var.- ious fkinds .of substances in gaseous or `liquid phases :and semi-solids, as well `as -iiuids .containingxnacroand micro solids 'in a new and .efficient manner.

.Gne objectof :the invention Vis @to .provide certain improvements in the form yof construct-ion disclosed in .my Veo-.goending 4application Ser. No. 535,626, filed May 11, 1944, now Letters Patent No. 12,442,234. dated May 25, `1948, .wherein the agglomerated Isolids and 'masses Yare `forced outvardiy :into `contact .with inclined deilectors or vanos which tend iso-'force theaggllomerated solids andmasses downwardly Vfor dischargaWhereas in the present improy/ements the outwardly forced agglomerated -solids and masses are yco1- lected inchannels the walls of which co-'act with the=moving solids andmasses to establish therein a ieldo centrifugal -orce eiTec-tive to cause a further agglomeration of the solids Land masses into larger'bodies capable of gravitation.

.Another object of the `invention "to provide an improve-:l iltering apparatus for separating micro particles land suspensoids from a uihd wherein the particles and suspensoids are sulojectedLtoa Ield of yentriiugal `force, due to the rotation of a -iiltering medium, tor effect progressive agglomeration -or coagulation thereof 'into mossos ood tho mossos oro thon oobiooboi toa second field o f centrifugal force counter in directioi'i 'to 'that of the-rotating Amedium to effect aglnle'ltoil 0f the Lgglmead '31315515.1515' Wiiereloythe latter-'are capable o f girayigtating to ,a receiver. ,Another object ofihorinveimon-1sio prono@ improved lforno ,oooorotos boring io foto es filtering :Woll through Whoh .the .fluid .to 11.6.111- terod posses :and on' outer woollioltmirg with tho altering ,Woll o ,ohoaroloor 'into zwiioil .material .is Supplied, the rotation of tho .liorns 'Wollorv- 1.1% "Q0 fthenfllal311319110? i.l hhmner `to force the `solid portions of ,the .material outwardly, and spacedly-disposed means on tlfie "outer Wall arranged to collect 'the outwardly forced material and vimpart spiral ,moyernenrit thereof to establish acentrifugalnuence therein in a .direction '..oountor to that :of 'teo rotatif@ of vthe -lterne Wall., the ofooi .of -rhio P99 cause .aeelomerotion rof the separatori out solle portions into masses capable of eroi/Noting 31.0 a receiver.

,Another .obiect .of the ,invention is to Prot/ido an imprese@ filtering apparatus having .an inner rotatable Sintentos rivali through which the fluid passes and er1-.outer wall forming with theinnor wall .a chamber, .an ,inlet .opening Yfor ,material and a dischargeiogening at .theloyrer endof the chamber, the Lrotation .of fthe :inner avail .Serving to establish outwardly thereof a primary eld or .centri:iugai iorce. Iwhich eectime `to .Sepe amate the .solids .and/.or particles iffrom ,the sup: plied material, restrain y,them from 'lodgement on :the ,filtering wall .and cause agglomeraton of thesolids and/o1' particles ntomasses, and means on the router `Wall for collecting the solids and masses .and :efiective lto provide ftherein .a seconde-.ry :field :of centrifugal force :to .cause va ,further vagglomeration `of .the solids and .masses .into larger abodies .-.capable .of .gravitent-ing `to and discharge through fthe disclarge opening.

other objects .of the invention 'twill' be apparent Pto it'hose v.skilled in the `art .-to which my in- `volition :relates from the following .description taken Lconnection with the accompanying drawingsnwlheren Fig. f1 isla View partly in -.elevation and partly in .section .cfa lteringiapparatus embodyinglny invention. f

Eig. 32 :is afseotion on theLl-fine f2--2-of lEig. 1.

Eig. 3 is Lal-.section similar tol-Fig. 12, `out-showing a modied lformof construction.

Rigori iis-a section simi-lante Fig. 3,1but enlarged toshow thedirection of vflow of the Yiwilt'rate and -agglomeration of Lthe particles' and suspensods into masses .and .bodies lof solid materia-ls'.l

fEig. L5 iis ia Asection similar Lto ilig. `2, lout showing .another imooli'ed form of construction.

"Eig 6 "is .a traeinen:tarysection of `vthe "-'iltering member .of :sectional form adapted lfor `use Whereia large 'volume vor'material iis suppliedto the apparatus :and ltered.

vInthe .drawings il indicates as an entirety an outer .casing 4to :which the -materiallto be @filtered :is-delivered f2 `rindicates as an entirety -l'tering or separating means Within the casing -I driven'py a suitable-:motor 3, preferablyfnounted oo .the ooms 'Ibrimoono1o'oilorookot 3o, n'ooiinootod :rotation 'to the @todos ,or 'separates moans to ,illustrato 'one form off grinfie 1 afirmaron In-the form of construction shown in Figs. "1

u to 4, inclusive, the filtering or separating means consist of a casing 2' having an annular wall 2a: which is formed of porous or foraminous material and through which the ltrate flows to effect filtration or separation of the supplied material, this wall being rotated about its axis by the motor 3 (as hereinafter set forth) to establish outwardly thereof a centrifugal force effective to act on those portions of the material that are to be separated therefrom.

By preference, the filtering wall forms the side wall of the casing 2', which is bodily rotated by the motor 3.

As set forth in my aforesaid co-pending application (now Letters Patent No. 2,442,234, dated May 25, i948), the apparatus is adapted to operate on a wide range of materials. Accordingly, the size of the openings in the filtering wall will depend upon the kind or character of material to be ltered, its pressure and the speed of rotation of this wall; also, where the material to be filtered consists of a liquid, the speed of rotation of the filtering wall and the size of the openings therein will depend upon both the viscosity and pressure of the liquid. Y

The outer casing I consists of upper and lower heads la, Ib, formed with annular seats for an annular wall I and secured together and to the wall I by bolts Ic. The opposite ends of the wall I' engage suitable gaskets le provided in the seats, whereby the casing I is made liquid tight. Either head or both heads Ia, Ib, may be provided with suitable instrumentalities (not shown), whereby the apparatus may be mounted on a suitable support or frame of a machine depending on the specific application of the apparatus. In the form of construction disclosed the wall I is formed of transparent material, such as glass. The head la is formed with an inlet la', the walls of which are preferably provided with screw threads to receive and mount a nipple 4, removably connected by a coupling 4a to a supply pipe 5, through which the material to be filtered or operated upon is supplied under pressure. In the preferred form of construction, the pipe 5 is connected to the outlet end of a suitable rotary pump lV supported on brackets 6a which are secured to the casing of the motor 3, the rotor of the pump 6 being drivingly connected to the shaft of the motor 3, whereby one motor is utilized to drive both the inner casing 2 and pump 5. The material to be operated upon is suppliedvunder pressure by gravity or otherwise by a pipe 'I suitably connected to the inlet end or side of the pump 6. The pump E being disposed in close relation to the outer casing I, it insures delivery of the material through the inlet la' into the casing I at adequate pressure to insure flow of the ltered material into the casing 2', whereas the casing 2 is rotated, the effect of which is to establish outwardly thereof a centrifugal force which acts on the heavy and/or solid portions of the supplied material in opposition to the pressure thereof to prevent accumulation of such portions on the filtering wall of the casing 2' and outward movement thereof as later set forth. Accordingly, it is advantageous to provide a pump in close relation to the inlet for the casing I to insure a uniform supply of the material at the proper pressure thereto. Ihe head Ia is provided with an annular upwardly extending collar 8 on which is removably mounted a cap 9 to form a chamber I0, the side wall of the collar being formed with a screw threaded outlet opening to which a discharge 4 pipe II (later referred to) is connected. The lower head Ib is formed with one or more openings Ib' (six openings Ib in annular arrangement being shown) through which that portion of the material, which is prevented from ltering through and into the inner casing 2', gravitates or is directed, as later set forth, into a receptacle i2, removably related to the head Ib. By preference, the receptacle i2 is provided with a ange 12a formed with openings, so that certain of the bolts Ic may be extended through the head Ib and flange I2a and engaged by nuts Ic for removably supporting the receptacle on the vhead ib. As shown, a gasket 12b is provided between the flange ld and head Ib to prevent leakage from the casing I. The bottom wall of the receptacle I2 is provided with one or more valved drain openings L21: leading to a receiver I2' removably supported on the bottom wall of the receptacle I2. For this purpose the side wall of the receptacle I2 is provided with a flange I2C which is engaged by a flange IZd on the open end of the receiver i2. The flanges l2c, Zd, are formed with alined openings, so that the extended ends of those bolts Ic which support the receptacle l2 on the end' wall Ib, may extend through the openings and by means of wing nuts i2e removably secure the receiver I2 in position. r)The valve for the drain openings |21 consists of a disk i2f, which is fixed to the upper end of a shaft i2g extending through and rotatably mounted in the bottom walls of the receptacle i2 and receiver i2'. The lower end of the shaft I2g is provided with a removable handle I2g (preferably consisting of a wing nut), whereby the disk I2f may be rotated. The bottom wall of the receptacle I2 is preferably formed with two diametrioally related openings I2x and the disk iff is formed with similarly related openings 12;" so that in one position of the disk I2f the openings Iza: are closed and in another position thereof the openings I2f, 2112, are in registered relation, whereby the collected solids in the receptacle l2 may be discharged into the receiver i2', following which the disk I2f is rotated to close the openings Icc. By removing the nut 12g', the receiver I2 may be removed and emptied of the solids therein and replaced. By this arrangement, the solids may be removed without stopping the ltering operation.

The casing 2' comprises the following: 2a indicates a hollow shaft mounted axially of the casing I and preferably closed at its lower end by a threaded plug I3. As the shaft 2a is hollow, it may be utilized as the conduit for the filtrate from the inner side of the wall 2:1: to the discharge pipe. The lower end of the shaft 2a loosely fits an upstanding collar or boss iSaprovidedontheinner face of the head Ib. The lower end of the collar i3d is closed by a screw plug Ita. The opposed faces of the plugs I3, I3a', are formed with related recesses in which is mounted a ball I4 to provide an anti-friction and thrust bearing for the shaft 2a. The upper end of the shaft 2a extends through alined openings formed in the head la and cap 9 for connection by means of a suitable coupling I5 with the shaft of the motor 3. A gasket I5a is interposed between the parts of the coupling I5 to prevent the escape of the filtrate from the shaft 2a. The casing I is provided with anti-friction bearings i6 for the upper end of the shaft 2a. In the arrangement illustrated the upper end of the cap 9 is recessed as shown at 9a to accommodate the anti-friction bearings I6 between it and the shaft 2a, the

`bea-ring i6 being secured in position by an annu lar ring il, removably bolted to the cap ill. -I 8', 48a, indicate spaced v-ugpper land lower heads having a hollow boss l 8b, fitting the sha-ft 1a and removably secured thereto by a set screw +80. The inner 'fa-ces ci the xheads 18, 18a, adjacent their peripheries, -ar-e lformed zwith all-ned recesses l which -torni sea-ts for the opposite ends of the porous or iorami-nous wall 21x. It will be understood that the wa-1l '2r may 'be of any desired thickness and the openings therethrough may be of varying sizes for 'reasons already set forth. Where Aa porous wall `is employed, it may be 'for-med of carborundum, carbon, Iconfipressed powdered metal or artieial stone. The seats 119 are preferably annular and the wall '2st ls `preterably formed of asinglesection of material shapedv in cross section to removably t Athe seats 19, whereby the casing 2' is of true cylindrical form, but the invention is not to 4be limited 'to a wall of this cross-'sectional sha-pe, since the vvcentrifugal -orce set -up due to the 'rotation iof vthe cas ing 2^" will -be effect-ive where this wall is ysectional or o-i Vsome other shape. Suitable Agaskets 2| are interposed between the opposite ends rof the wall 2r and the bottoms of the seats r9 to prevent leakage of the ltrate from the easing 2'. The side walls of the shaft '2a 1loetweenthc -heads i8, lau, are formed fwith a plurality of lopenings 22, to -pernrit Aflow of the `Amaterial filtered `through the wall or zone 2r into the shaft 2a. That portion of theshaft 2a-ex-tending through the cham ber Il) -is formed Awith la plurality of openings 23 (preferably elongated longitudinally of the shaft) to discharge the iiltrate into the chamber yIll tor discharge 'through 'the pipe M. T-he side walls 'of 'the openings act centri-ideally von the iil- :trate flowing up through the shaft ito increase the flow thereof into and through the pipe Il.

24 indicates a pair of `plates surrounding `and `closely tting the shaft 2a within `the chamber F0 and engaged -by `a .coiled expansion spring :24a `which normally :holds :the plates in engagement lfwith Vthe bottom wall .of the ohamber ill) and iii-- '-nerface'o thecaple. L251indicates a suitable seal 'mounted in an annular-recessfformed inthe lower side or face .of .the '-head lla .and havinga :spring operated sealing .element engaging :the shaft 12a Ato prevent `the escape .of material inthe casing Il,

due :to pressure oit-.capillary attraction. into the chamber IB. :21e ndicatesasuitablesealrmounted Vln an annular :recess formed vin the 02.10B below the :bearing :le .and navinga spring operated sealing .element engagingrthe :shaf'tza to prevent the .escape .of material in ythe chamber vIll into the :bearing and outwardly therethrough.

To divert the material lin the casing l away :from .the bearing yUl and seal A25, II provide on the shaft 12a adjacent eachof these parts -a plurality nr set of outwardlyfextendingarms lor wings 2r', the revolution of :which by :the shaft imparts :movement .to the ,material outwardly. In the :form or lconstruction shown the arms or `vwings 12m' fof each set ponsist 1of ridges embossed .on a

:drietal disk which yis provided with a collar ,.se-

@cured to ithe shaft 2a in ,any desired manner.

2:1 indicates la plurality of collecting ymembers spaced. uniformly around the inner face of the YWall LI., each :member being lof Vsubstantially -U- :shape :in `cross section, `to Aprovide va curvilinear 4.bottom Wall `,and side walls 21a for a purpose later :set forth 'The :members ;-2.-1 are disposed .at an angleitoftheiaxisofthe-.casing I andextend from the head la to the head lo, `with.theirlovver ends sin registry with-the Aopenings lb', respec- (h tively. .one side wall Iof each member is suitably iixed to the wall l and mounted with respect tothe casing so :that the .space between the side walls of the member opens in n direction counter to the direction of rotation -of the 'wall 2r. The members 21 cornet with the rotating wall 2.a' and 'centrifugal torce established thereby, as later set forth. s The members Al! .on the Wall l serve Vas barriers fia) which prevent rotative movement of the Ematerial y(or portions .thereon supplied :to .the easing .1 due tofrictional `routard; of the ,casing fi."l therewith and :(111) :set up a turbulence or agitation yin the material, whereby the 'heavy or solidfportions thereof may :be more readily separated from the flu-id portion. 'By pre.- venting rotation ofjthe material in the :casing l., the .outer surface lof the wall 2m Iozf the casing 2 is lcontinuously Washed 'by portions .fof the ma.- terial without unduly affecting lthe ow lo! fthe liquid material-through the wall 2x `due to vthe pressure vof the material supplied to the casing In operation, the material is supplied yinto 'fthe' casing l .under pressure for contact with Vthe *lff tering Wall 2m, which being of a porous charac ter, permits the 'liquid or fluid portion of the ma terial to now therethrough finto theicasing 2 from which it llows through `the shaft 2a to 'the cham ber l0 for discharge :through-the pipe fll. 'Duefizo the revolution of the A.wall 2m a `Acentritugal force or zone is established on its outer surface and the 'liquid or fluid material adjacent thereto, which force acts on the heavy andflor solid por? 'tions oi the supplied -ii'iza.terial to impart an out ward movement thereof away from thewall 2o: and hence prevents suoli portions from iaccumu, lating or Jbeing deposited on this Wa-ll. As there is a continuous supply-of the material .to the :cass ing l and a continuous centrifugal Yforce dm. parted to the heavy lor solid portion-s thereof. the latter are rforced outwardly and then down wai-diy into the receptacle t2 due to the .angular arrangement of the fdeiiectors 2l. Accord.- ngly, it will 'be observed that vthe filteringwall 2x is automatically maintained Ifreeofthoseporrtions of the material which would vclog for tend to -olog the Lpores thereof, so 'that'the supplied material is `rapidly and eiciently inltered. It will be observed that the rate of flow or pressure offthe supplied vmaterial must be regulated or the speed of the casing 2' be lregulated so 'that zthe'cen trifugal force established will not prevent'theiinilow of material into the casing'Z, butvv`iIl-mer. ate effectively upon the heavier land/or solidipor tions of thematerial without-unduly affecting the `:flow of the filtrate into casing'2. In other'fwords,

the speed 'of Athe ycasing 2" mustbe related '4to-or balanced against the pressure of fthe `supplied material. Where the ymateria-l to 'be .filtered-isla liquid, this speed and pressuremustvbe-regulated with respect tothe viscosity of the material, to insu-re ow of the yliquid or Afluid at -a :predetenmined rate and rapid Aand einoient operation'. As shown, the mot-or 3 is directly `coupled to 'the shaft 2a and pump 6, yso -that =the latter designed for a predetermined capacity -in relation to lthe speed of the casing 2' and viscosityof the material to be supplied l'to the casing fl. AVIt :will -be obvious that a suitable 'speed-change mechanismmaybe interposed 'between the imotor '3 and shaft 2a or between the motors 'and pump to niet-:t varying conditions, dependent yupon the kind and/or viscosity of thefmaterial to loe-operated upon; or a variable speed vmotor may fbe `employed and .the pump -t driven by .a Yseparate lmotor.

1 'It will be observed that the type, character or construction of the wall 2r will depend upon the kind of material to be iltered and/or the character or size of the heavy particles Vor bodies therein. For example, this wall may consist of sheet metal formed with openings of any desired size, or wire mesh of any desired screen capacity per square inch.

On the other hand, this wall 2x may be adapted to separate out the heavier portions of immiscible liquids. In employing a liquid of this character the macro solids or particles are progressively forced outwardly and caused to unite or agglomerate with other particles into larger sizes or masses, as shown at as (see Fig. 4) and these masses may in turn unite or agglomerate into still larger masses, as shown at As these masses :c' and as are under the influence of the centrifugal force, and the rotation of the wall 2m tends to move them in a general circular direction (see arrows z in Fig. 4), the masses are Vforced into the collecting members 21, the curvilinear bottom and side walls of which guide the larger masses into a spiral rotating body to establish therein a secondary field of centrifugal force counter to that established by the rotating wall 211:, thereby causing a further or supplemental agglomeration of the masses to form larger .bodies of solid materials capable of freely gravitating downwardly into the receiver agglomerating operation is progressively effected to form and accumulate these bodies in the members 21 and the walls of the latter are disposed at an inclined angle, the centrifugal force on the previously agglomerated masses tends to supplement the gravitational influence to impart a rapid downward flow of these bodies. It will be observed that the members 2T operate as collectors for the masses as well as guide means for directing them downwardly. Where the fluid to .t

be filtered contains microorganisms or particles in the solid and/ or liquid phase, they are caused to agglomerato progressively by action of the primary centrifugal force until the combined agglomerated organisms or particles build up into masses having a size capable of being further acted upon by the secondary centrifugal force in the manner already set forth, whereby bodies of solid materials are formed and directed downwardly through the members 2l.

The outer side wall of each member 2'! may be substantially parallel to its inner side wall, as shown in Figs. 1 and 2, but by preference, the outer side wall of each member 2l is curved inwardly, as shown at 2lb (see Figs'. 3 and 4) to direct the moving masses in a spiral direction, whereas its outer edge portion is curved outwardly as shown at 21o to allow a maximum intake of the masses into the member 2i.

Fig. 5 illustrates a form of construction wherein the outer or terminating edge portion of the outer side wall of each member is curved inwardly from Vend to end thereof to prevent the escape of the solid bodies during their now to the adiacent opening Ib'. Y

Where a continuously supplied relatively large volume of material is to be iiltered, the inner or ltering casing of the apparatus is constructed as shown in Fig. 6 to simplify the manufacture and assembly thereof. In this form of construction, the casing consists of a plurality of annular sections 28, having on their circumferential upper and lower edges complementary seating elements 28a to support them in alined axial relation, the lowermost section being mounted on an adapter 29 the lower end of which is suitably l2; as the ,A

fixed to a hollow shaft 30. The shaft 30 is formed with inlet openings 30a and mounted and driven in the manner already set forth with respect to the shaft 2a. The side wall of each section 28 is formed of suitable porous material. In this form of construction any number of sections 28 may be employed to provide a ltering wall of any desired area. The uppermost section is provided with an adapter (not shown) suitably connected to the shaft 3B, these adapters serving to connect the shaft 30 to the sections 28, whereby the latter are rotated therewith to establish a centrifugal force outwardly thereof, while permitting the liquid to lter through the sections for discharge through the shaft 30.

No claim is made herein to the subject-matter of my aforesaid co-pending application, now Letters Patent No. 2,442,234.

To those skilled in the art to which my invention relates, many changes in construction and widely differing embodiments and applications thereof will suggest themselves without departing from the spirit and scope of the invention. My disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

What I claim is:

, l. In a filtering apparatus, the combination of a substantially liquid tight casing consisting of upper and lower end walls and a side wall, .means for supplying material under pressure to said casing, a separate casing mounted within said first mentioned casing to rotate about a vertical axis and provided with a porous side wall through which the material is filtered, outlet connections for the nitrate leading from the interior of said separate casing through one of said end walls, means for rotating said separate casing to effect a centrifugal force on the heavy particles of the material, the lower end wall of said first mentioned casing being formed with openings through which the heavy particles are discharged, and collectors disposed in spaced relation adjacent to and around the inner surface of the side wall of said first mentioned casing and connected at their lower ends to said discharge openings, respectively, the walls of each said collector being curvilinear and of substantially U-shape in cross section, the opening between the sides of each collector being in opposed relation to the direction of rotation of said separate casing to receive the heavy particles of the material forced outwardly under the influence of the centrifugal force, and arranged to direct the heavy particles into spiral paths the effect of which is to cause agglomeration of the particles into masses for gravitating endwise of said collector to and through the adjacent discharge opening, said collectors being inclined to the axis ci said rst mentioned casing to supplement the gravitational effect on the masses. f 2. An apparatus as claimed in claim 1 wherein a collecting receptacle is provided on the lower end of said iirst mentioned casing for the masses -discharged through said discharge openings, a receiver removably secured to the walls of said receptacle, and valv-e means are provided between said receptacle and said receiver.

3. An apparatus as claimed in claim 1 wherein the outer side of each collector is provided from end to end thereof with an extension which is bent inwardly and extends parallel and in spaced relation to said side toward the bottom of the adjacent collector.

4. In apparatus of the class described, the com- 2,670,849 9 10 bination of a casing consisting of upper and lower members consisting of curvilinear walls of subnd walls and an annular side wall, .said lower stantially U-shape in cross section forming an supplying into said casing iiuid under pressure 5 the outwardly forced particles into a spiral in a to be filtered, filtering means within said casing direction counter to that of said rotatable and connected to an outlet in the latter, said member.

filtering means including a hollow member hav- RUSSELL P. DUNMIRE.

lower end walls and providing a iiow connection 10 References Cited in the file of this patent from th-e interior of said member to said outlet, UNITED STATES PATENTS the side wall of sald member consisting of an annuior porous sido wou through which the nitrate Number Name Datelgl ows from said casing into said member, means 9g8450 'Homans Dec' 1g' 1910 for rotating said member to establish outwardly 15 12 21146 Ward et al Apr' 9 g of said porous side Wall a centrifugal influence to 2'144418 Schramm Jan 17 93 force the heavy particles of the uid away from 2338779 Mutcl Jan' 11' 44 said porous side wall, and spacedly related collect- 21442234 Dunmfre May 25' lga ing members for the heavy particles spaced from 2'596384 Dunmlre May 13' 1 2 said porous wall and associated wthfand extend- 20 FOREIGN PATENTS ing longitudinally of the side wal o said casing and each connected at its lower end to one of Numgfzo Gregg "133281912 

